1. Field of the Invention
The present invention relates to a communication terminal having a wireless communication facility including transmission and reception of a message, a time control program storage medium storing a time control program which is executed in the communication terminal and controls the time of the communication terminal, a message center for intermediating for a message sent from a sending terminal and sending it to a receiving terminal, and a remote time setting program storage medium storing a remote time setting program which is executed in the message center and remotely sets the time of the communication terminal.
2. Description of the Related Art
Recently, a communication terminal of a mobile telephone, etc. has become widespread, and is loaded with not only a simple telephone facility, but also various facilities such as an electronic mail facility, a camera facility, an electronic money facility, thus presenting an aspect of total information processing equipment for personal use. Most of the communication terminals having various facilities are provided with a time display facility, and using the facility an increasing number of users use the communication terminal for a watch.
The above-mentioned communication terminal has a time correction facility, and when the time is not correctly set, it can be correctly set using the communication terminal. However, the time setting operation is unexpectedly troublesome, and a number of users hesitate to correctly set the time.
Under such circumstances, the technology of automatically setting the time of a communication terminal by wireless has been suggested.
For example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-206276) proposes a communication terminal capable of automatically setting the time by loading the function of a radio clock in a communication terminal.
Patent Document 2 (Japanese Patent Laid-Open No. 2002-156477) proposes the technology of setting the time of the communication terminal by preparing, for example, a car navigation device loaded with a GPS (global positioning system) for a communication terminal, extracting time data from the GPS data after receiving the GPS data using the device, and sending the time data to the communication terminal over a network. The document also describes setting the time for a communication terminal by taking the delay time in communications through the network into account.
Patent Document 3 (Japanese Patent Laid-Open No. 2000-287273) discloses the technology of setting the time of a PHS (personal handyphone system) having a clock facility by setting time data in a message to be sent from a base station to the PHS.
In the technology of loading a radio clock for a communication terminal disclosed by the above-mentioned patent document 1, although the time of the communication terminal is correctly set, it is necessary to implement new hardware of a radio clock in the communication terminal, whereby producing a costly system.
Furthermore, the technology of intermediating with a car navigation device, etc. disclosed by the above-mentioned patent document 2 requires such a new intermediate device, thereby producing an entirely expensive system, and producing a personal clock correction system of, for example, being used only as a communication terminal of the same user as the device, etc. and is not used for the entire subscriber terminals.
Additionally, the technology described by the patent document 3 of sending a message including time data set from the base station to the PHS terminal requires no additional hardware, but it is necessary to add or amend software of the PHS terminal and the base station. However, although the software of both a PHS terminal and a base station is changed, the time delay of a message sent through a communication path is not considered. Therefore, the problem of the cost required for adding or improving the software occurs, and the high precision time correction facility corresponding to the cost cannot be realized, thereby incurring unbalanced cost and facility.